Such numbering machines are used when continuous or randomly determined serial numbers are to be applied to a printed object, especially a document, for example, when printing blank checks, banknotes or identity papers. A typical example of such a numbering machine is the Leibinger PC LEN device, which is used, for example, in Heidelberg GTOZ-NN-52 model printing presses for printing checks. Information on these devices can be found, for example, in the prospectus “High Security Numbering” of the firm of Leibinger.
Such a numbering machine has a housing with a wheel axle, which is arranged in the housing removably for maintenance, cleaning or for replacement with another font and on which a plurality of number wheels can be arranged rotatably. It is noted that the designation “number wheel” does not represent, in the sense of this patent specification, any limitation to numbers, and the term is rather used synonymously with the designation “print wheel.”
Simple removability of the wheel axle is important for making it possible to carry out the cleaning and maintenance operations necessary after the printing process.
The number wheels are each adjustable one by one and at least one number wheel can be driven by means of a gear wheel associated with the number wheel. The numbering machine has a drive shaft with a drive pinion connected to the drive shaft for each number wheel connected to a drive unit, so that rapid setting of a desired combination of fonts is guaranteed.
A plurality of numbering machines are often arranged on a shaft of a printing press in case of the usual use of such numbering machines in order to make a rapid and continuous printing process possible. The bulkier the individual numbering machines, the greater is the minimum distance between serial numbers, which can be printed with two numbering machines arranged adjacent to one another on a shaft. The more number wheels are arranged on the wheel axle, the more serious becomes the problem, because an increasing number of drive axles—and also an increasing number of motors in case of numbering machines driven by motor—must be accommodated in a given space.
This leads to the effort to make available numbering machines of the most compact design possible in order to also apply number sequences on crowded, small formats.